Dotcom-MonitorThis is an excellent site with multiple speed tests available. Also available are a number of paid and free apps for developing and testing web pages and other web applications including servers, streaming, network and email applications. .Highly recommended.

WhichVOIP This is a useful free tool
which can specifically help if you are looking to assess the speed and quality of your connection for using things like Skype, FaceTime or a VOIP provider such as Vonage. (Note - I was not able to use this test page with Google Chrome, but tested it using Internet Explorer. It also requires the most recent version of Java.